Patent document 1: JP 2002-183475 A
Portable terminals such as cellular phones having a function to detect positions have been spreading in recent years. The position detecting function is used for a server to provide services that distribute service information such as coupon information and advertisement information according to the positions of the portable terminals. Moreover, Patent document 1 discloses a configuration to enable electronic commerce in in-vehicle apparatuses mounted in vehicles.
Further, in-vehicle apparatuses such as navigation apparatuses have a function to detect positions and time-series variations of the positions. Comparing the position detecting function of the in-vehicle apparatus with that of the portable terminals results in the following. The in-vehicle apparatus detects positions in reference to, in addition to detection results of the GPS receiver, detection results of other sensors such as a distance sensor or a gravitation sensor, monitoring results of vehicle information via a in-vehicle local area network such as a controller area network (CAN), and detail map information. In contrast, the portable terminal detects positions in reference to simple map information in addition to detection results of the GPS receiver, therefore providing a position detection accuracy lower than that of the in-vehicle apparatus.
This may preclude a significantly accurate detection of the position of the portable terminal to which the service information is provided, namely, the position of the user to which the service information is provided, in the service that distributes the service information from the server to the portable terminal using the position detecting function of the portable terminal. This may therefore not preclude a possibility to determine the position of the user inaccurately or incorrectly. Such a case may result in providing the service unsuitable to the position of the user or not providing the service sufficiently suitable to the position of the user.